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diff --git a/src/base/random_mt.cc b/src/base/random_mt.cc
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+/*
+ * A C-program for MT19937, with initialization improved 2002/1/26.
+ * Coded by Takuji Nishimura and Makoto Matsumoto.
+ *
+ * Before using, initialize the state by using init_genrand(seed)
+ * or init_by_array(init_key, key_length).
+ *
+ * Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ *
+ * 3. The names of its contributors may not be used to endorse or
+ * promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *
+ * Any feedback is very welcome.
+ * http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
+ * email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
+ */
+
+#include "base/random.hh"
+
+/* initializes mt[N] with a seed */
+void
+Random::init(uint32_t s)
+{
+ mti = N + 1;
+ mt[0] = s & (uint32_t)0xffffffff;
+
+ for (mti = 1; mti < N; mti++) {
+ mt[mti] = 1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti;
+ /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
+ /* In the previous versions, MSBs of the seed affect */
+ /* only MSBs of the array mt[]. */
+ /* 2002/01/09 modified by Makoto Matsumoto */
+ mt[mti] &= (uint32_t)0xffffffff;
+ /* for >32 bit machines */
+ }
+}
+
+/* initialize by an array with array-length */
+/* init_key is the array for initializing keys */
+/* key_length is its length */
+/* slight change for C++, 2004/2/26 */
+void
+Random::init(uint32_t init_key[], int key_length)
+{
+ int i = 1;
+ int j = 0;
+ int k = (N > key_length) ? N : key_length;
+
+ init(19650218);
+
+ for (; k; k--) {
+ mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * (uint32_t)1664525))
+ + init_key[j] + j; /* non linear */
+
+ mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
+
+ i++;
+ j++;
+
+ if (i >= N) {
+ mt[0] = mt[N - 1];
+ i = 1;
+ }
+
+ if (j >= key_length)
+ j = 0;
+ }
+
+ for (k = N - 1; k; k--) {
+ /* non linear */
+ mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1566083941UL)) - i;
+
+ /* for WORDSIZE > 32 machines */
+ mt[i] &= (uint32_t)0xffffffff;
+ i++;
+
+ if (i >= N) {
+ mt[0] = mt[N - 1];
+ i = 1;
+ }
+ }
+
+ /* MSB is 1; assuring non-zero initial array */
+ mt[0] = (uint32_t)0x80000000;
+}
+
+/* generates a random number on [0,0xffffffff]-interval */
+uint32_t
+Random::genrand()
+{
+ uint32_t y;
+ static uint32_t mag01[2] = { 0, MATRIX_A};
+
+ if (mti >= N) { /* generate N words at one time */
+ int kk;
+
+ for (kk = 0; kk < N - M; kk++) {
+ y = mt[kk] & UPPER_MASK | mt[kk+1] & LOWER_MASK;
+ mt[kk] = mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x1UL];
+ }
+ for (; kk < N - 1; kk++) {
+ y = mt[kk] & UPPER_MASK | mt[kk+1] & LOWER_MASK;
+ mt[kk] = mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
+ }
+
+ y = mt[N - 1] & UPPER_MASK | mt[0] & LOWER_MASK;
+ mt[N - 1] = mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1UL];
+
+ mti = 0;
+ }
+
+ y = mt[mti++];
+
+ /* Tempering */
+ y ^= (y >> 11);
+ y ^= (y << 7) & (uint32_t)0x9d2c5680;
+ y ^= (y << 15) & (uint32_t)0xefc60000;
+ y ^= (y >> 18);
+
+ return y;
+}